Ceiling-mounted RFID-enabled tracking

ABSTRACT

Systems and methods for tracking a subject using radio-frequency identification (RFID). In an embodiment, an antenna array comprising a plurality of articulating brackets and a plurality of antennas is provided. Each of the articulating brackets is configured to move one of the plurality of antennas into a plurality of positions, and each of the antennas is configured to receive a RFID signal. In addition, a processor receives RFID data based on RFID signals received by the antennas of the antenna array, and determines a trajectory of a subject based on the RFID data. Based on the determined trajectory of the subject, the processor controls one or more of the articulating brackets to move one or more of the antennas into a position to track the subject.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/838,237, filed on Dec. 11, 2017, which is a continuation of U.S.patent application Ser. No. 15/237,400, filed on Aug. 15, 2016, which isa continuation of U.S. patent application Ser. No. 14/189,883, filed onFeb. 25, 2014, which claims priority to U.S. Provisional Patent App. No.61/768,924, filed on Feb. 25, 2013, which are all hereby incorporatedherein by reference as if set forth in full.

BACKGROUND Field of the Invention

The embodiments described herein are generally directed to radiofrequency identification (RFID) tracking apparatuses, and, moreparticularly, to methods and apparatuses for reading and trackingtransponders associated with a subject (e.g., an object, human, animal,etc.), using ceiling-mounted and/or floor-mounted RFID-enabled trackingapparatuses.

Description of the Related Art

The technique of identifying objects using radio-frequencycommunications has been eponymously called radio-frequencyidentification (RFID). RFID systems have been employed in anincreasingly wide range of applications such as retail supply chain,postal logistics, healthcare, manufacturing, retail stores, and airportbaggage tracking. In retail supply chain applications, RFID has beenused to track and trace goods throughout the supply chain, automate thereceipt of pallets of shipments at distribution centers, increaseshipping accuracy of goods from distribution centers (DCs) to stores,and manage inventory throughout the supply chain. In postal logisticsRFID has been used to monitor the quality of service of postal shipmentsfor international and national mail systems. For instance, a globalpostal organization has deployed RFID to over forty countries around theworld (and increasing) to measure and monitor quality of service of maildelivered between those countries. In healthcare, RFID is being used forasset and resource management, as well as patient and staff tracking forimproving patient flow within hospitals. In airports, specificallybaggage tracking, RFID is being used as a replacement to barcode-basedsystems for quicker, more secure, and more accurate transfer of bags toimprove the overall baggage handling rate.

Accordingly, RFID systems have been increasingly employed in diverseapplications to facilitate the identification and tracking ofmerchandise, personnel, and other items and/or individuals that need tobe reliably monitored and/or controlled within a particular environment.The introduction of RFID into these application has resulted in moresecure, efficient, and accurate systems.

SUMMARY

In an embodiment, an apparatus for tracking a subject using RFID isdisclosed. The apparatus comprises: an antenna array comprising aplurality of articulating brackets and a plurality of antennas, whereineach of the plurality of articulating brackets is configured to move acorresponding one of the plurality of antennas into a plurality ofpositions, and wherein each of the plurality of antennas is configuredto receive a RFID signal; and at least one processor that receives RFIDdata based on one or more RFID signals received by one or more of theplurality of antennas of the antenna array, determines a trajectory of asubject based on the RFID data, and, based on the determined trajectoryof the subject, controls one or more of the plurality of articulatingbrackets of the antenna array to move one or more of the plurality ofantennas into a position to track the subject.

In another embodiment, a method for tracking a subject using an antennaarray comprising a plurality of articulating brackets and a plurality ofantennas is disclosed, wherein each of the plurality of articulatingbrackets is configured to move a corresponding one of the plurality ofantennas into a plurality of positions, and wherein each of theplurality of antennas is configured to receive a radio-frequencyidentification (RFID) signal. The method comprises using at least onehardware processor to: receive RFID data based on one or more RFIDsignals received by one or more of the plurality of antennas of theantenna array; determine a trajectory of a subject based on the RFIDdata; and, based on the determined trajectory of the subject, controlone or more of the plurality of articulating brackets of the antennaarray to move one or more of the plurality of antennas into a positionto track the subject.

BRIEF DESCRIPTION OF THE DRAWINGS

The details of the present invention, both as to its structure andoperation, may be gleaned in part by study of the accompanying drawings,in which like reference numerals refer to like parts, and in which:

FIG. 1 is a schematic diagram that illustrates a tracking apparatusconfigured to perform a tracking operation, according to an embodiment;

FIG. 2 is a flow chart illustrating a method for performing a trackingoperation, according an embodiment;

FIG. 3 is an assembly view (a top perspective view) of a trackingapparatus, according to an embodiment;

FIG. 4 is a view of the adjustable bottom panel, including the automaticidentification (Auto ID) system of the tracking apparatus in FIG. 3,according to an embodiment; and

FIG. 5 is a view of the tracking apparatus in FIG. 3, situated above aceiling and configured to track a RFID-enabled subject, according to anembodiment.

DETAILED DESCRIPTION

In some embodiments, a tracking apparatus can be used to obtaininformation from a RFID-enabled subject such as, for example, an object,human, animal, etc. In some embodiments, such a tracking apparatus canbe used to track the subject. For example, the tracking apparatus can beused to track a medical instrument that can potentially be moved withina hospital building. In other embodiments, such a tracking apparatus canbe used to track, and further monitor and/or control activities ormovements of the subject. For example, the tracking apparatus can beused to monitor activities and movements of a patient, therebyfacilitating a response to and care for the patient in a timely manner.

As shown and described with respect to FIG. 4, a tracking apparatus caninclude a RFID reader, antenna array, and one or more sensors,indicators, and/or communication devices. As shown and described withrespect to FIGS. 3-5, such a tracking apparatus can be mounted on or ina ceiling (e.g., above or below a ceiling). In other embodiments, atracking apparatus, similar or identical to the ones shown and describedherein, can be installed at any suitable location such as, for example,an indoor wall, an outdoor wall, a roof, a pillar, a floor, etc. Forinstance, such a tracking apparatus can be installed below a high raisedfloor (e.g., mounted to a high raised floor tile grid) in, for example,a data center.

Furthermore, the tracking apparatus can be operatively coupled to acontrol device (e.g., a server at a remote location) via a suitableconnection (e.g., a wired and/or wireless connection). The trackingapparatus can receive configuration information, control commands,and/or instructions from the control device. The tracking apparatus canalso send collected data or information (e.g., RFID data associated withan object, human, or animal being tracked) to the control device. Insome embodiments, the control device can be operatively coupled to andcontrol the operation of multiple tracking apparatuses, each of which issimilar or identical to those shown and described herein. In someembodiments, the control device can include or be communicativelycoupled to a centralized database that is used to collect and processdata received from the tracking apparatus(es).

As used herein, a module can be, for example, any assembly and/or set ofoperatively-coupled electrical components associated with performing aspecific function, and can include, for example, a memory, a processor,electrical traces, optical connectors, software (executing in hardware),and/or the like. As used herein, the singular forms “a,” “an,” and “the”include plural referents unless the context clearly dictates otherwise.Thus, for example, the term “an Auto ID read module” is intended to meana single module or a combination of modules configured to automaticallyread and process data associated with a subject being tracked.

FIG. 1 is a schematic diagram that illustrates a tracking apparatus 100configured to perform a tracking operation, according to an embodiment.The tracking apparatus 100 includes a mounting plate 102 and a baseplate 105, where the mounting plate 102 is operatively coupled to (e.g.,mounted to) the base plate 105. The mounting plate 102 hosts or mountsan automatic identification (Auto ID) system 110 configured to performthe tracking operation. As described in detail below, such an Auto IDsystem 110 can be configured to perform the tracking operation byautomatically and in real time (or near real time) collecting, reading,and processing data associated with a subject being tracked. In someinstances, the Auto ID system 110 can implement one or more automaticidentification and data capture (AIDC) technologies to automaticallyidentify subjects, collect data about them, and enter that data directlyinto computer systems (i.e., without human involvement). AIDCtechnologies include, for example, barcodes, passive RFID (including LF(low frequency), HF (high frequency), UHF (ultra-high frequency),microwave, etc.), battery-assisted passive (BAP) RFID, active RFID(including LF, UHF, Wi-Fi, Bluetooth®, Zigbee®, ultrasound, infrared,UWB (ultra wide band), etc.), biometrics (e.g., iris and facialrecognition system), magnetic stripes, optical character recognition(OCR), smart cards, voice recognition, surface acoustic wave (SAW)-basedsensors, etc.

As shown in FIG. 1, the mounting plate 102 can also include a powersource module 108 operatively coupled to the Auto ID system 110. Thepower source module 108 can be any device, component, or moduleconfigured to provide power to the components of the Auto ID system 110.Such a power source module 108 can include, for example, a device togenerate power from renewable energy source(s) (e.g., solar, wind, heatdifferential from heating, ventilation, and air conditioning (HVAC)systems, etc.), battery, alternating current (AC) power cord, directcurrent (DC) power cable, and/or the like. The base plate 105 provides abase to the mounting plate 102 and attaches the tracking apparatus 100to a fixed structure such as a ceiling, a wall, a floor, or the like.For example, as shown and described with respect to FIGS. 3 and 5, thebase plate 105 can be mounted to a ceiling such that the trackingapparatus 100 can be used to track subjects (e.g., objects, humans,animals, etc.) that are located and/or move under the ceiling.

In an embodiment, the tracking apparatus 100 is operatively coupled to acontrol device 180 via one or more networks 170. The control device 180can be any device that can be used to configure components of the AutoID system 110 to control the tracking operation performed by the Auto IDsystem 110. Moreover, the control device 180 can receive data (e.g.,RFID data and/or data derived from RFID data) from the trackingapparatus 100 and further process the received data. For example, thecontrol device 180 can be a server, a workstation, a computing device,and/or the like.

In some embodiments, the control device 180 can include a tag dataprocessing component such as, for example, a tag acquisition processor(TAP). In such embodiments, the control device 180 can be configured tostore and execute software (e.g., intelligent algorithms of TAP) relatedto tag data processing. Some technologies related to TAP are disclosedin U.S. Pat. No. 7,667,572, filed on Jul. 29, 2005 and entitled “RFIDTag Data Acquisition System,” U.S. Pat. No. 7,667,575, filed on Jul. 29,2005 and entitled “Location Virtualization in an RFID System,” U.S. Pat.No. 7,567,179, filed on Oct. 16, 2006 and entitled “ConfigurationManagement System and Method for Use in an RFID System Including aMultiplicity of RFID Readers,” International Patent Pub. No.WO/2006/015349, filed on Jul. 29, 2005 and entitled “RFID Tag DataAcquisition System,” and International Patent Pub. No. WO/2007/047677,filed on Oct. 16, 2006 and entitled “Configuration Management System andMethod for Use in an RFID System Including a Multiplicity of RFIDReaders,” all of which are hereby incorporated herein by reference intheir entireties. Additionally, in some embodiments, the control device180 can include or be associated (e.g., communicatively coupled) with acentralized database that is used to store some or all of the datareceived from the tracking apparatus 100.

As shown in FIG. 1, in some embodiments, the control device 180 can beoperatively coupled to the tracking apparatus 100 via network(s) 170.Network(s) 170 can include any type of backhaul communication networkthat is configured to enable communication and data transmission betweenthe control device 180 and the Auto ID system 110. The network(s) 170can comprise a wired network (e.g., an Ethernet, local area network(LAN), etc.), a wireless network (e.g., a wireless local area network(WLAN), worldwide interoperability for microwave access (WiMAX), longterm evolution (LTE) network, general packet radio service (GPRS)network, satellite and terrestrial network, etc.), or a combination ofwired and wireless networks (e.g., mobile communication network, theInternet, etc.). For example, the control device 180 can be a serverplaced at a centralized location in a building and connected, via alocal area network (LAN), to multiple tracking apparatuses (similar oridentical to the tracking apparatus 100) that are distributed andinstalled at different locations (e.g., ceilings, floors, walls, etc.)within the building. As another example, the control device 180 can be acomputing device located at a data center and operatively coupled, via acampus area network (CAN), to tracking apparatuses that are installed atmultiple buildings. As yet another example, the control device can be avirtual server or a cloud server hosted within the Internet. In otherembodiments, the control device 180 can be connected, using a wired orwireless connection (e.g., a serial connection, RS485 connection, CAN(controller area network) bus, fieldbus, etc., or any other suitableindustrial communication standard), to the tracking apparatus 100without using a network or intermediate device.

In the embodiment illustrated in FIG. 1, the Auto ID system 110 includesa processing device 130, a sensor 140, an indicator 150, a communicationdevice 160, and an antenna array 120, each of which is attached to themounting plate 102 and operatively coupled to each other (e.g., throughthe mounting plate 102). In some embodiments, the Auto ID system 110 caninclude more or less components as shown in FIG. 1. For example, theAuto ID system 110 can include more than one sensor, no sensor, morethan one indicator, no indicator, etc.

The antenna array 120 can include a set of antennas of the same ordifferent types that can be used to receive signals from RFID-enabledsubjects (e.g., via a tracking transponder). Each of the antennas fromthe antenna array 120 can be attached to the mounting plate 102 using,for example, an articulating bracket. In some embodiments, thearticulating bracket can be adjustable such that the positioning andorientation of the antenna connected to that articulating bracket can beadjusted. Additionally or alternatively, the antennas from the antennaarray 120 can be self-learning, self-adaptive, and/or self-healingantennas that are configured to automatically learn from the environmentand adapt its configurations (e.g., positioning and/or orientation) tomeet one or more requirements and/or preferences of radio frequency (RF)transmission.

For example, antenna array 120 can be self-learning in that, if no readsare seen on specific antenna(s) or from specific direction(s), based ona current RF pattern of the antennas, then the system (e.g., processingdevice 130) can switch or move antenna(s) at random speed(s) or torandom pattern(s) to optimize them for RFID reads. Additionally oralternatively, antenna array 120 can be self-adaptive in that theantenna(s) may change gain or polarization to adapt to a given zonebased on reflections and multipath effects. Additionally oralternatively, the antenna array 120 may be self-healing, wherein theantenna(s) have special material properties that maintain the gain,tuning, and/or RF pattern of the antenna(s) based on the environment,temperature variations, etc.

The sensor 140 can be any type of sensor configured to detect a subject(e.g., an object, human, animal), such as, for example, a motion sensor,a temperature sensor, a vibration sensor, a sound sensor, and/or thelike. The indicator 150 can be any type of device that, when activated,can display or present an indication. Such an indicator can be, forexample, a light-emitting diode (LED) display, an alarm speaker, and/orthe like. The communication device 160 can be any device configured tosend data signals to and/or receive control signals from the controldevice 180. Such a communication device can include, for example, a dataport, a wireless access point (WAP), a wireless modem (e.g., forsatellite communication, GPS (global positioning system) communication,terrestrial communication, etc.), a Bluetooth® transceiver, and/or thelike.

In an embodiment, the processing device 130 includes a processor 135, amemory 138, and/or other components (not shown in FIG. 1). The processor135 may include a positioning module 132, a detecting module 134, anAuto ID read module 136, and/or other modules (not shown in FIG. 1). Insome embodiments, although not shown in FIG. 1, the processor 135 caninclude a software-defined radio (SDR) module configured to implement aSDR system for the Auto ID system 110.

Each module in the processor 135 can be any combination ofhardware-based module (e.g., a field-programmable gate array (FPGA), anapplication specific integrated circuit (ASIC), a digital signalprocessor (DSP)), software-based module (e.g., a module of computer codestored in the memory 138 and/or executed at the processor 135), and/or acombination of hardware- and software-based module. In an embodiment,each module in the processor 135 is capable of performing one or morespecific functions associated with the tracking operation. In someembodiments, the modules included and executed in the processor 135 canbe, for example, a process, application, virtual machine, and/or someother hardware or software module (stored in memory and/or executing inhardware). The processor 135 can be any suitable processor configured torun and/or execute those modules. For example, the processor 135 caninclude and/or execute a software-based and/or hardware-based (e.g.,configured to execute software stored in hardware) module related to theself-learning, self-healing, and/or self-adapting process of theantennas from the antenna array 120. As another example, the processor135 can include and/or execute a software-based and/or hardware-based(e.g., configured to execute software stored in hardware) module thatstores received data (e.g., in the memory 138) when the connectionbetween the Auto ID system 110 and the control device 180 is notreliable, and/or forwards the data to the control device 180 when areliable connection is established.

In an embodiment, the positioning module 132 can be configured to adjusta position and orientation of each of and/or subsets of the antennasfrom the antenna array 120. For example, the positioning module 132 cansend a signal to an articulating bracket such that the articulatingbracket adjusts the position and/or orientation of the attached antenna.The detecting module 134 can be configured to, based on signals receivedfrom the sensor 140, detect a subject (e.g., an object, human, animal,etc.) and activate the antenna array 120 and the Auto ID read module136. The Auto ID read module 136 can be configured to automatically, andin real time (or near real time), process data (e.g., RFID data)received from the antennas that track the subject, and then provide theprocessed data to the control device 180.

In some embodiments, the memory 138 can be, for example, a Random-AccessMemory (RAM) (e.g., a dynamic RAM and/or static RAM), a flash memory, aremovable memory, and/or so forth. In some embodiments, instructionsassociated with performing the tracking operation can be stored withinthe memory 138 and executed by the processor 135. In an embodiment, aninstruction or command associated with adjusting the position of anantenna from the antenna array 120 can be received at the processingdevice 130 from the control device 180. The instruction can be stored inthe memory 138 and executed by the processor 135. Specifically, thepositioning module 132 can send a signal to the articulating bracket ofthe corresponding antenna, such that the position of that antenna isadjusted based on the instruction.

FIG. 2 is a flow chart illustrating a method 200 for performing atracking operation, according an embodiment. The code comprisinginstructions to perform the method 200 can be stored in, for example, anon-transitory, processor-readable medium (e.g., the memory 138 inFIG. 1) in a processing device (e.g., the processing device 130 shownand described with respect to FIG. 1). Particularly, the processingdevice can be included in an Auto ID system of a tracking apparatus,such as the tracking apparatus 100 shown and described with respect toFIG. 1. The tracking apparatus can be operatively coupled to a controldevice, such as the control device 180 shown and described with respectto FIG. 1. The code stored in the non-transitory, processor-readablemedium (e.g., the memory 138 in FIG. 1) of the processing device can beexecuted by a processor of that processing device (e.g., the processor135 in FIG. 1). The code includes instructions to be executed by theprocessor to cause the processing device to perform the operationsillustrated in FIG. 2 and described below.

At 202, the processing device can receive, from a sensor (e.g., sensor140 shown and described with respect to FIG. 1), a signal associatedwith a tracking target (e.g., an object, human, animal, etc.). Thesignal can be received at the processing device in response to thetracking target being detected by the sensor. For example, the trackingapparatus can be installed in, on, or at a ceiling (e.g., above theceiling or below the ceiling) of a corridor in a hospital building. Whena patient walks through the corridor, a motion sensor of the trackingapparatus can detect the movement of the patient, and then send a signalto the processing device of the tracking apparatus.

At 204, the processing device can activate an indicator (e.g., theindicator 150 in FIG. 1) and an antenna array (e.g., the antenna array120 in FIG. 1) of the tracking apparatus in response to receiving thesignal. Specifically, a detecting module (e.g., the detecting module 134in FIG. 1) of the processing device can send signals to the indicatorand the antenna array, such that the indicator and the antenna array areactivated. As a result, the antenna array can be changed from a sleepmode to an operating mode, and an indication that the tracking is inoperation can be displayed by the indicator. In the above example, inresponse to the signal received from the motion sensor, a detectingmodule (e.g., the detecting module 134) of the processing device cansend a signal to activate the antenna array (e.g., the antenna array120) such that the antennas from the antenna array start to track thepatient. Meanwhile, the detecting module can send a signal to activate ablinking LED (e.g., indicator 150) to indicate that a tracking operationis in action.

At 206, the processing device can receive data associated with thetracking target from the antenna array. The received data can includeRFID data retrieved from signals that are sent from, for example, a RFIDtag (e.g., a passive RFID tag, an active RFID tag, a BAP RFID tag, etc.)attached to the tracking target (i.e., a subject, such as an object,human, animal, etc.). The RFID data can include, for example, dataassociated with the identification and/or status of the tracking target.The received data can also include or derive information that can beused to track the movement of the tracking target, such as signalstrength and/or direction of the received data. In response to receivingthe signals from the tracking target, the antennas from the antennaarray can retrieve the RFID data from the signals, and then send theRFID data and other information to the processing device for furtherprocessing. Alternatively, the antennas can communicate the signals tothe processing device, and the processing device may retrieve the RFIDdata from the signals.

In the above example(s), the tracking target may be a patient who iswearing a wristband that includes a RFID tag uniquely associated withthat patient. Antennas from the antenna array can receive signals sentfrom the RFID tag, retrieve RFID data associated with the RFID tag fromthe received signals, and send the RFID data as well as otherinformation and/or data of the received signals to the processingdevice.

At 208, the processing device can determine an identification and/orstatus of the tracking target and data associated with a trajectory ofthe tracking target. Specifically, an Auto ID read module (e.g., theAuto ID read module 136 in FIG. 1) of the processing device can read andanalyze the RFID data, and then determine the identification and/orstatus of the tracking target based on the RFID data. Furthermore, theAuto ID read module (or another component or module of the processingdevice) can infer data associated with the trajectory of the trackingtarget based on the data received from the antenna array such as thesignal strength, sampling rate, direction, phase, and/or time span ofthe signals received at the antennas. In the above example, an Auto IDread module of the processing device can identify the RFID tag of thepatient based on the RFID data that is uniquely associated with the RFIDtag. Thus, the patient can be identified. Furthermore, based on the datareceived at the processing device that is associated with the signalsreceived at the antennas, the Auto ID read module can determine thetrajectory of the patient as the patient walks through the corridor.

At 210, the processing device can send the identification of thetracking target and data associated with the trajectory of the trackingtarget to the control device for further processing. In someembodiments, a communication device (e.g., the communication device 160in FIG. 1) of the tracking apparatus can be used to send theidentification and data to the control device. For example, dataassociated with the identification and trajectory of the patient can besent to a server at a surveillance room in the hospital building forfurther processing. Such a server can be operatively coupled to andcontrol the operation of a set of tracking apparatuses that aredistributed within the building.

At 212, the processing device can receive, from the control device, aninstruction associated with adjusting an orientation of an antenna fromthe antenna array. In some embodiments, such an instruction can bedefined by a closed-loop system that provides feedback to the antennaarray based on a projected trajectory of a tracking target.Alternatively, antennas of the antenna array or other components (e.g.,sensors) of the tracking apparatus can be manually adjusted orconfigured by, for example, a user of the tracking apparatus. As anexample, a projected or inferred trajectory of the patient may show thatthe patient is approaching a boundary of coverage of the antenna array.Based on such a projected trajectory, the control device (e.g., as apart of the closed-loop system) can determine to adjust the orientationof one or more antennas from the antenna array such that the coverage ofthe antenna array is extended. The control device can then define aninstruction for the adjustment, and send the instruction to theprocessing device of the tracking apparatus.

At 214, in response to receiving the instruction, the processing devicecan send a signal to the corresponding antenna, such that theorientation of the antenna is adjusted based on the instruction.Specifically, a positioning module (e.g., the positioning module 132 inFIG. 1) of the processing device can perform such an operation. In someembodiments, as shown and described with respect to FIGS. 1 and 4, thepositioning module can send a signal to adjust an articulating bracketof the antenna or multiple articulating brackets for multiple antennas,such that the orientation of the antenna(s) are changed based on theinstruction. For example, the processing device can send a signal toadjust the orientation of a corresponding antenna such that the trackingapparatus can continue tracking the patient.

Although described with respect to FIGS. 1 and 2 as a processing deviceof a tracking apparatus performing the operations 202-214, in otherembodiments, a portion of those operations can be performed by othercomponents or devices of the tracking apparatus or other devices. Forexample, a sensor of the tracking apparatus (e.g., motion sensor) can beconfigured to detect a subject and then activate an indicator and/or anantenna array without sending a signal to the processing device. Asanother example, a centralized data processing device operativelycoupled to the tracking apparatus can be configured to process datacollected by the tracking apparatus and determine the identification,status, and/or trajectory of the subject being tracked. In such ascenario, the tracking apparatus can send raw data (e.g., RFID dataand/or other data associated with received signals) collected by theantennas to the data processing device without performing the processingoperations as described at 208.

FIG. 3 is an assembly view (an isometric view) of a tracking apparatus300, according to an embodiment. The tracking apparatus 300 can bestructurally and functionally similar or identical to the trackingapparatus 100 shown and described with respect to FIG. 1. Specifically,the tracking apparatus 300 can include a mounting plate 10, one or moremounting brackets 14 (e.g., four mounting brackets 14), and/or a baseplate 12. The mounting plate 10 can be mounted to the base plate 12. Themounting plate 10 is attached to an adjustable bottom panel, which isunder the mounting plate 10 and not viewable in FIG. 3. As shown anddescribed with respect to FIG. 4, the adjustable bottom panel of themounting plate 10 includes an Auto ID system (e.g., the Auto ID system110 shown and described with respect to FIG. 1). Additionally, althoughnot shown in FIG. 3, the tracking apparatus 300 can be operativelycoupled to and controlled by a control device (e.g., the control device180 shown and described with respect to FIG. 1).

Without popping a ceiling tile, it can be very difficult to identify theavailable space for installation of a RFID read point. Space above theceiling can be occupied by a building's structure, HVAC ducting, cabletrays, plumbing, etc. Advantageously, to meet these stringent spacerequirements, the height of the ceiling-mounted apparatus, according todisclosed embodiments, can be adjusted on the spot without tools. Thisis made possible, for instance, by embodiments which utilize a slidermechanism with embossed measurements, such that the mounting brackets 14(e.g., four mounting brackets 14) may be adjusted to the same or varyingheights to meet the space requirements. These mechanisms may alsoimprove human safety and efficiency for installers working at elevatedheights (e.g., using a ladder or indoor scissor lift) to install theceiling-mounted apparatus(es). Since, in some embodiments, no tools areneeded to install the apparatus or adjust the height of the apparatus,the installer may keep one hand free to improve safety, for example, byallowing the installer to hold on to the ladder or a rail of the scissorlift.

Specifically, in such embodiments, the mounting brackets 14 may comprisea slider mechanism and a clip 14-4. As illustrated, the slider mechanismcomprises a groove, slot, or track 14-1 through which a sliding element14-2 fits and along which the sliding element 14-2 slides. The slidingelement 14-2 is fixed to base plate 12 on one side of the track 14-1 andclampable or securable on the other side of the track 14-1 via aclamping or securing mechanism 14-3, such that the sliding element 14-2may slide along the track 14-1 when unclamped and fixed at a positionalong the track 14-1 when clamped. For instance, the sliding element14-2 may comprise a screw which is threaded through a through-hole onthe base plate 12, opposite the track 14-1, and passed through the track14-1 such that the threads of the screw extend beyond the track 14-1 onthe side of the track 14-1 opposite the base plate 12. As illustrated,the securing mechanism 14-3 may comprise a clamping piece and a wing nutor similar element. The clamping piece contacts a surface of themounting bracket 14 and surrounds the screw threads extending throughthe track 14-1. The wing nut can be tightened over the screw threads inthe direction of the clamping piece to tightly press the clamping pieceagainst the mounting bracket 14, thereby releasably or adjustably fixingthe base plate 12 to the mounting bracket 14 (e.g., via the frictionbetween the clamping piece and the mounting bracket 14 or othermechanism). Alternatively, the slider mechanism may comprise apush-to-release spring-loaded stopper, a combination of spring-loadedlocking pins, or similar element(s), which may be, for example, receivedby any of a plurality of holes formed in the track 14-1 so as to fix thebase plate 12 at a position along the track 14-1 corresponding to thehole. In an embodiment, mounting bracket 14 may be embossed or otherwisemarked with measurements, to aid in the positioning of each of themounting brackets 14 with respect to base plate 12. Thus,advantageously, using the slider mechanism and mounting brackets 14, theheight of the tracking apparatus 300, which may be directly attached tobase plate 12 or indirectly attached to base plate 12 via mounting plate10, may be easily adjusted without any tools or with limited use oftools.

Furthermore, the mounting brackets 14 may each comprise a clip 14-4,which is configured to mount on standard ceiling tile grids. Thus,advantageously, the mounting brackets 14, along with the trackingapparatus 300 which may be directly attached to base plate 12 orindirectly attached to base plate 12 via mounting plate 10, can beeasily installed on existing ceiling tile grids without any tools orwith limited use of tools and without any modification to the ceilingtile grid. In addition, as discussed above, the height of the trackingapparatus 300 with respect to a ceiling tile, over which the trackingapparatus 300 has been placed, may be easily adjusted.

In some embodiments, the tracking apparatus 300 can be mounted to aceiling in a substantially horizontal position (e.g., above a ceilingtile as shown in FIG. 5). As described herein, the use ofceiling-mounted tracking apparatuses (e.g., with the software andcommunication features described in the '014 Patent) allows RFID readpoints to connect to multiple antennas to create individual or combinedzones. Advantageously, compared to wall-mounted RFID reader devices,this may reduce overall reader count for a given space by leveragingeach antenna as a read point with multiple antennas/read pointsconnected to a single RFID reader.

Specifically, as shown in FIG. 3, the base plate 12 can be attached totwo mounting brackets 14 that can be connected, for example, to asupport grid of the ceiling (e.g., as shown in FIG. 5). Alternatively,the mounting plate 10 can be directly mounted to the mounting brackets14, in which case, the tracking apparatus 300 may not include the baseplate 12. The mounting brackets 14 can be compatible with any type ofceiling rails. The tracking apparatus 300 can be mounted to a ceiling ata position above the ceiling, for example, to conceal the apparatus suchthat it cannot be seen from under the ceiling. Alternatively, thetracking apparatus 300 can be mounted to a ceiling at a position underthe ceiling, for example, to minimize impact of dust on the trackingapparatus 300. In other embodiments, although not shown and describedherein, the tracking apparatus 300 can be mounted at any other suitablelocation and/or with any other appropriate position. In suchembodiments, the tracking apparatus 300 can operate and perform thetracking function in a similar or identical method as described herein.For example, the tracking apparatus 300 can be mounted to a wall of aroom in a substantially vertical position to track subjects (e.g.,objects, humans, animals) inside the room.

In some embodiments, the mounting plate 10 and the base plate 12 can beintegrated together and attached using hardware (e.g., screws,actuators, grooves, cables) in such a way that the position ororientation of the mounting plate 10 can be altered to optimize orimprove the performance of the Auto ID system of the tracking apparatus300. For example, the distance between the mounting plate 10 and thebase plate 12 can be adjusted such that the mounting plate 10 can bepositioned at an appropriate height to provide optimized or improvedsignal strength for data transmissions. As another example, the mountingplate 10 can be rotated to a certain angle (e.g., rotated within ahorizontal plane, rotated within a vertical plane, or rotated in anyother suitable direction) with respect to the base plate 12 that is in afixed position, to provide a different coverage for the tracking.Similarly, in other embodiments, the mounting plate 10 can be mounted,integrated, or attached to the mounting brackets 14 in an adjustablemethod such that the position or orientation of the mounting plate 10can be altered to optimize or improve the performance of the Auto IDsystem of the tracking apparatus 300. Together, the mounting plate 10,the mounting brackets 14, and/or the base plate 12 can provide a methodof anchoring via, for example, cable, hooks, or other anchoring methods.

FIG. 4 is a view of the adjustable bottom panel including the Auto IDsystem of the tracking apparatus 300, according to an embodiment. Asshown in FIG. 4, the Auto ID system of the tracking apparatus 300includes an antenna array 18, a RFID reader 16, and an accessory device27 containing other components (e.g., sensor, indicator, communicationdevice) of the Auto ID system. Each of the antenna array 18, RFID reader16, and accessory device 27 is attached to the mounting plate 10.Furthermore, the antenna array 18, RFID reader 16 and the accessorydevice 27 are operatively coupled to each other via, for example, cables(e.g., at the other side of the mounting plate 10 and not viewable inFIG. 4).

As shown in FIG. 4, the antenna array 18 includes four antennas of thesame type. Each of the four antennas is connected to an articulatingbracket 20. The articulating brackets 20 are adjustable such that theposition and/or directionality of the antennas can be changed to provideoptimized or improved performance (e.g., coverage, read rate, signalstrength, accuracy of tracking) of the Auto ID system. In someembodiments, the position and/or directionality of an antenna from theantenna array 18 can be manually adjusted by, for example, a user of theapparatus. In other embodiments, the position and/or directionality ofthe antenna can be automatically adjusted. For example, one or more ofthe articulating brackets 20 can be configured to receive an instructionfrom the control device and then make an adjustment to the positionand/or directionality of the corresponding antenna based on theinstruction.

The four antennas of the antenna array 18 can be collectively configuredto track a subject (e.g., object, human, animal). In some embodiments,the antennas are positioned in a manner and/or their directionalitiesare adjusted to certain directions such that each antenna can cover acertain space with minimum overlap between coverage of the differentantennas. For example, an antenna from the antenna array 18 can createan exclusion zone for the remainder of the antennas from the antennaarray 18. In some embodiments, the antennas can have overlappedcoverage. For example, an antenna from the antenna array 18 can createan inclusion zone for the remainder of the antennas from the antennaarray 18. In such embodiments, the RFID reader 16 can be configured toprocess RFID data associated with the same subject that is collected bydifferent antennas. Furthermore, in some embodiments, the antennas canbe coordinated (e.g., by a processor of the tracking apparatus 300 or bythe control device) to perform the tracking operation. For example, if asubject is within the coverage of two antennas, the two antennas can becoordinated to alternate in performing the tracking.

In an embodiment, each antenna in the antenna array 18 can be adjustedindependently and/or as subsets in order to create one or more RFIDzones. The antenna(s) can be adjusted (e.g., by adjusting correspondingarticulating bracket(s)) through a variety of angles to provide suchzones in virtually any direction. However, it should be understood that,it may be preferable to design the antennas such that they may bearticulated to some subset of angles within a range of 0° to 180° withrespect to an orthogonal axis to the surface to which they are mounted(e.g., ceiling, floor, wall) and may be rotated to some subset ofpositions within a range of 0° to 360° with respect to an axis that isparallel to the surface to which they are mounted. In this manner, eachantenna or subset of antennas can be articulated towards any point (orvirtually any point, depending on the design) on the side of the surfaceto which the tracking apparatus 300 is mounted.

In some embodiments, although not shown in FIG. 4, the antenna array 18can include more or less than four antennas of the same or differenttypes. In some embodiments, the mounting plate 10 can be coupled to oneor more bulkheads such that the tracking apparatus 300 can be connectedto one or more additional tracking apparatuses (e.g., similar oridentical to the tracking apparatus 100 or 200 described herein) usingthe bulkhead(s) via, for example, coaxial cable or any other suitableconnecting means. As a result, the size of the antenna array can beincreased. Furthermore, in some embodiments, the mounting plate 10 caninclude devices or components used to add or couple antennas onto themounting plate 10 such as, for example, multiplexer(s), powersplitter(s), combiner(s), circulator(s), etc.

The RFID reader 16 can be any device configured to receive, process,and/or send RFID data. In some embodiments, the RFID reader 16 can bestructurally and/or functionally similar to the processing device 130shown and described with respect to FIG. 1. That is, the RFID reader 16can include modules (e.g., software-based modules, hardware-basedmodules, or a combination of software-based and hardware-based modules)configured to perform functions unrelated to processing data (e.g., RFIDdata) such as, for example, detecting a subject (using a sensor),adjusting position or orientation of an antenna, etc. In otherembodiments, the RFID reader 16 can be configured to solely process data(e.g., RFID data), and the other functions can be performed by othercomponents, devices or modules (e.g., the accessory device 27) of thetracking apparatus 300.

Particularly, the RFID reader 16 can identify the subject being trackedby reading the RFID data sent from a RFID tag disposed with the subject.Specifically, the RFID reader 16 can be configured to receive RFID datathat is collected by the antenna array 18, identify the subject beingtracked based on the RFID data, determine data (e.g., location, speed,direction) associated with the subject based on the RFID data, and sendthe identifier and inferred data of the subject to the control device.

In some embodiments, one or more sensors, indicators, and/orcommunication devices of the tracking apparatus 300 can be embeddedwithin the accessory device 27. In other embodiments, although not shownin FIG. 4, the sensor(s), indicator(s) and/or communication device(s)can be positioned and attached to the mounting plate 10 at separatelocations. A sensor of the tracking apparatus 300 can be any type ofsensor configured to detect a subject (e.g., an object, human, animal).For example, the tracking apparatus 300 can have a temperature sensorconfigured to detect a human based on a temperature of the human bodythat is higher than temperatures of the environment and surroundingobjects. As another example, the tracking apparatus 300 can have amotion sensor configured to detect an object, human, and/or animal thatmoves at a speed higher than a threshold. For yet another example, thetracking apparatus 300 can have a sensor (e.g., smoke detector, odorsensor, etc.) configured to detect a dangerous situation (e.g., smoke,fire, poison gas, etc.) and then activate an indicator (e.g., an alarmsiren, a flashing light, etc.) to signal subjects (humans, objects,animals) to evacuate (or to be evacuated). In such an example, the AutoID system of the tracking apparatus 300 can be used to track and countthe subjects being evacuated. In some embodiments, the trackingapparatus 300 can have more than one sensor of the same or differenttypes to detect the same or different types of subjects.

In some embodiments, when no subject is detected by the sensor(s) of thetracking apparatus 300, the tracking apparatus 300 can operate in asleep mode. For example, the antenna array 18 and the RFID reader 16 canbe turned off or placed in an inactive status. When a subject isdetected by the sensor(s), the tracking apparatus 300 can be changedfrom the sleep mode to an operating mode. For instance, a signal can besent (e.g., from the sensor) to the antenna array 18 and the RFID reader16 such that the antenna array 18 and the RFID reader 16 can be turnedon or changed to an active status. Additionally, in some embodiments, asignal can be sent by the communication device(s) to the control device,such that an indication of the tracking being in operation can be sentto the control device and, in some embodiments, provided from thecontrol device to an operator of the control device. Meanwhile, in anembodiment, a signal can be sent to an indicator(s) of the trackingapparatus 300 such that an indication of the tracking being in operationcan be shown or presented. Such an indicator can be any type of devicethat can be used to display or present an indication such as, forexample, a visual indicator, an audio indicator, and/or the like. Forexample, when a subject is detected, a light can be turned on, a beepingsound can be played, a blinking LED light can be activated, and/or analarming siren can be triggered.

A communication device of the tracking apparatus 300 can be any device,component, or module configured to send data signals to and/or receivecontrol signals from the control device. Such a communication device caninclude, for example, a WAP or a wireless modem operatively coupled tothe control device via a wireless connection, a data port operativelycoupled to the control device via an Ethernet connection, or acombination of wireless and wired connections. As described above, thecommunication device can be configured to send an indication of thetracking operation to the control device. Similarly, the communicationdevice can be configured to send data (e.g., RFID data) or informationprovided by the RFID reader 16 to the control device, and/or receiveconfiguration information (e.g., to configure the RFID reader 16) and/orcontrol instructions (e.g., to adjust the position or orientation of theantenna array 18) from the control device. Additionally, thecommunication device can be used together with the RFID reader 16 totransmit detection signals and/or RFID data to the control device.

In some embodiments, the components of the Auto ID system of thetracking apparatus 300 can be powered by an external power source suchas, for example, a wired connection (e.g., power over Ethernet (PoE)),an electrical outlet (connected via an electrical wire), and/or thelike. Alternatively or additionally, the components of the Auto IDsystem can be powered by an internal component (not shown in FIG. 4) ofthe tracking apparatus 300 (e.g., the power source module 108 shown anddescribed with respect to FIG. 1). Specifically, such an internal powersource component can include, for example, a device to generate powerfrom renewable energy source (e.g., solar, wind, heat, etc.), a battery,and/or the like. For example, a battery power source component can beinstalled and attached to the side of the mounting plate 10 opposite theside shown in FIG. 4.

FIG. 5 is a view of the tracking apparatus 300 situated above or withina ceiling and configured to track RFID-enabled subject, according to anembodiment. As shown in FIG. 5, the tracking apparatus 300 is mounted,via the two mounting brackets 14, to a ceiling support grid of theceiling 22. In some embodiments, the tracking apparatus 300 can bemounted in a way such that the antenna array 18 can interact withminimal interference with the RFID-enable subject. In some embodiments,as discussed above, the tracking apparatus 300 can be mounted to aceiling, a wall, a raised floor or other structure using any suitabletechnique (e.g., magnetic attachment, suction pads, pulley, drop cable,mounting bracket, etc.)

A tracking transponder can be used with, connected to, equipped with, orintegrated with a subject to be tracked. For example, a trackingtransponder can be attached to (or implanted into) a human's body (e.g.,implanted into a human's shoulder as the tracking transponder 24 shownin FIG. 5, integrated with a wristband or a necklace, etc.). As anotherexample, a tracking transponder can be integrated with (or connected to)an object (e.g., integrated with a purse as the tracking transponder 26shown in FIG. 5, connected to a medical equipment, attached to apatient's file folder, etc.).

In some embodiments, the tracking transponder can include a RFID tag,which can be used to uniquely identify the subject associated with thetracking transponder. Such a tracking transponder can be configured tosend signals containing RFID data associated with the RFID tag. Thesignals sent from the tracking transponder can be received by one ormore of the antennas of the tracking apparatus 300. Thus, the RFID dataassociated with the RFID tag, and other data or information associatedwith the signals sent from the tracking transponder can be received atthe RFID reader 16 from the antenna array 18. As a result, based on theRFID data associated with the RFID tag, the RFID reader 16 can identifythe subject being tracked.

Furthermore, based on characteristics (e.g., signal strength, phase,frequency or pattern) of the received signals, the RFID reader 16 candetermine information associated with the subject being tracked. Forexample, the location of an object (or equivalently, the distancebetween the object and the antenna) can be determined based on signalstrength of the received signals. As another example, a speed ordirection of a moving subject being tracked can be inferred based on aseries of signals (e.g., can be sampled by the antenna) associated withthat moving subject. In some embodiments, the RFID reader 16 canimplement a tag data processing module (e.g., a TAP) to process receiveddata and signals. In such embodiments, the RFID reader 16 can beconfigured to store (e.g., in a memory of the RFID reader 16) andexecute software (e.g., by a processor of the RFID reader 16) related totag data processing such as, for example, intelligent algorithms of TAP,as described in the '014 Patent. For instance, the tag data processingmodule may translate characteristics of the received signal into alocation, distance, speed, trajectory, etc., by analyzing one or acombination of the following: (1) number of reads; (2) number of readsper antenna; (3) received signal strength indication (RSSI) captured byeach antenna; (4) time of arrival or phase of a signal at each antenna;and (5) exclusion zones created (e.g., one antenna can generate an RFbubble that can serve as an exclusion zone for another antenna and viceversa).

The RFID reader 16 can then send the identification, data, and/orinformation obtained from the RFID-enabled subject (e.g., received fromthe tracking transponder via the antenna(s) 18) to the control devicefor further processing. In embodiments, such tracking transponders canbe made in any suitable shape, size, model, and/or using any appropriatematerial, such that they can be used with different types of subjects(e.g., objects, humans, animals).

In some embodiments, a tracking apparatus (e.g., the tracking apparatus300) can be equipped with or included in a closed-loop system that canprovide feedback to the antenna array and/or the RFID reader of thattracking apparatus. The feedback can be associated with theconfiguration, orientation, or positioning of the antennas, and/orconfiguration or setting of the RFID reader. The feedback can be used toadjust the configuration, orientation, or positioning of the antennasand/or configure the RFID reader such that performance of the Auto IDsystem can be optimized or improved. The feedback can be used to modifyoperations of the tracking antennas and the RFID reader such as, forexample, signal strength, phase, frequency band, duration, samplingrate, function associated with detecting a particular RFID tag, etc. Insome embodiments, for example, when a subject being tracked moves toboundary of coverage of an antenna, feedback can be provided to adjustorientation of that antenna such that the antenna can keep track of themoving subject. For instance, this feedback may be used to determine alocation, distance, speed, trajectory, etc. of the subject being trackedby analyzing one or a combination of the following: (1) number of reads;(2) number of reads per antenna; (3) received signal strength indication(RSSI) captured by each antenna; (4) time of arrival or phase of asignal at each antenna; and (5) exclusion zones created (e.g., oneantenna can generate an RF bubble that can serve as an exclusion zonefor another antenna and vice versa). This information about thelocation, distance, speed, trajectory, etc. of the subject can then beused to adjust the antenna(s), e.g., towards a direction along thetrajectory of the subject being tracked.

Some embodiments described herein relate to a computer storage productwith a non-transitory computer-readable medium (also can be referred toas a non-transitory processor-readable medium) having instructions orcomputer code thereon for performing various computer-implementedoperations. The computer-readable medium (or processor-readable medium)is non-transitory in the sense that it does not include transitorypropagating signals per se (e.g., a propagating electromagnetic wavecarrying information on a transmission medium such as space or a cable).The media and computer code (also can be referred to as code) may bethose designed and constructed for the specific purpose or purposes.Examples of non-transitory computer-readable media include, but are notlimited to: magnetic storage media such as hard disks, floppy disks, andmagnetic tape; optical storage media such as Compact Disc/Digital VideoDiscs (CD/DVDs), Compact Disc-Read Only Memories (CD-ROMs), andholographic devices; magneto-optical storage media such as opticaldisks; carrier wave signal processing modules; and hardware devices thatare specially configured to store and execute program code, such asApplication-Specific Integrated Circuits (ASICs), Programmable LogicDevices (PLDs), Read-Only Memory (ROM) and Random-Access Memory (RAM)devices. Other embodiments described herein relate to a computer programproduct, which can include, for example, the instructions and/orcomputer code discussed herein.

Examples of computer code include, but are not limited to, micro-code ormicro-instructions, machine instructions, such as produced by acompiler, code used to produce a web service, and files containinghigher-level instructions that are executed by a computer using aninterpreter. For example, embodiments may be implemented using Java,C++, .NET, or other programming languages (e.g., object-orientedprogramming languages) and development tools. Additional examples ofcomputer code include, but are not limited to, control signals,encrypted code, and compressed code.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example only, and notlimitation. Where methods and/or schematics described above indicatecertain events and/or flow patterns occurring in certain order, theordering of certain events and/or flow patterns may be modified. Whilethe embodiments have been particularly shown and described, it will beunderstood that various changes in form and details may be made.

What is claimed is:
 1. An apparatus for tracking a subject using radio-frequency identification (RFID), the apparatus comprising: at least one motion sensor configured to detect movement; an antenna array comprising a plurality of articulating brackets and a plurality of antennas, wherein each of the plurality of articulating brackets is configured to rotate a corresponding one of the plurality of antennas into a plurality of orientations; and at least one processor configured to, in response to detecting movement of the subject, determine a trajectory of the subject based on one or more signals received by the antenna array, and, based on the determined trajectory of the subject, control a first articulating bracket of the antenna array to rotate a first antenna of the antenna array into a new orientation, relative to a second antenna of the antenna array, to track the subject.
 2. The apparatus of claim 1, wherein rotating the first antenna comprises changing a directionality of the first antenna to be directed towards the determined trajectory of the subject.
 3. The apparatus of claim 1, wherein determining the trajectory of the subject comprises determining a distance between the subject and one or more of the plurality of antennas based on the strength of the one or more signals.
 4. The apparatus of claim 1, wherein determining the trajectory of the subject comprises determining a location of the subject based on the strength of the one or more signals.
 5. The apparatus of claim 1, wherein the one or more signals received by the antenna array comprise a plurality of signals, and wherein determining the trajectory of the subject comprises determining a direction of the subject based on the plurality of signals.
 6. The apparatus of claim 1, wherein the one or more signals received by the antenna array comprise a plurality of signals, and wherein determining the trajectory of the subject comprises determining a speed of the subject based on the plurality of signals.
 7. The apparatus of claim 1, wherein the at least one processor is configured to control the plurality of articulating brackets such that directionalities of the plurality of antennas form a plurality of zones.
 8. The apparatus of claim 7, wherein two or more of the plurality of zones overlap.
 9. The apparatus of claim 1, further comprising one or more sensors that detect one or more environmental conditions.
 10. The apparatus of claim 1, wherein the at least one processor is configured to: operate the antenna array in a low power mode when no movement is detected; and operate the antenna array in an active power mode when movement is detected.
 11. The apparatus of claim 1, further comprising a transceiver configured to communicate with an external control device via a local area network.
 12. The apparatus of claim 1, wherein the at least one processor is configured to control the first articulating bracket to adjust the orientation of the first antenna, according to closed-loop feedback that is based on a projected trajectory of the subject.
 13. The apparatus of claim 1, further comprising a mounting plate attached to the antenna array, wherein the mounting plate is configured to be mounted on a ceiling.
 14. The apparatus of claim 13, further the mounting plate is configured to be mounted to the ceiling via one or more adjustable mounting brackets, wherein the one or more adjustable mounting brackets are configured to move with respect to the mounting plate to increase or decrease a distance between the mounting plate and the ceiling.
 15. The apparatus of claim 1, wherein the at least one processor is configured to automatically rotate one or more of the plurality of antennas if no reads are seen by those antennas in their current orientation.
 16. The apparatus of claim 1, wherein the subject comprises an RFID tag attached to an object.
 17. The apparatus of claim 1, wherein each of the plurality of articulating brackets is configured to rotate its corresponding antenna independently of any other one of the plurality of antennas.
 18. The apparatus of claim 1, wherein the at least one processor is configured to count a number of subjects whose trajectories are tracked.
 19. A method for tracking a subject using an antenna array, which comprises a plurality of articulating brackets and a plurality of antennas, wherein each of the plurality of articulating brackets is configured to rotate a corresponding one of the plurality of antennas into a plurality of orientations, the method comprising: detecting movement and, in response to detecting movement, determining a trajectory of a subject based on one or more signals received by the antenna array, and, based on the determined trajectory of the subject, controlling a first articulating bracket of the antenna array to rotate a first antenna of the antenna array into a new orientation, relative to a second antenna of the antenna array, to track the subject. 